RFR: JDK-8305993: Add handleSocketErrorWithMessage to extend nio Net.c exception message [v2]

[Matthias Baesken]

> Currently we get a rather strange exception in our jtreg tests :
> 
> java/nio/channels/DatagramChannel/AdaptorMulticasting.java
> 
> java.net.SocketException: Exec format error
> at java.base/sun.nio.ch.Net.joinOrDrop4(Native Method)
> at java.base/sun.nio.ch.Net.join4(Net.java:708)
> at java.base/sun.nio.ch.DatagramChannelImpl.innerJoin(DatagramChannelImpl.java:1606)
> at java.base/sun.nio.ch.DatagramChannelImpl.join(DatagramChannelImpl.java:1624)
> at Promiscuous.test(Promiscuous.java:176)
> at Promiscuous.main(Promiscuous.java:223)
> 
> The message could at least be improved, saying that setsockopt failed (plus providing the errno related text).
> Example is seen on macOS btw. .

Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:

  Move function to the top of file

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/13472/files
  - new: https://git.openjdk.org/jdk/pull/13472/files/811003c5..46ba11da

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13472&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13472&range=00-01

  Stats: 90 lines in 1 file changed: 45 ins; 45 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/13472.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13472/head:pull/13472

PR: https://git.openjdk.org/jdk/pull/13472